diff --git a/tests/Makefile.am b/tests/Makefile.am
index 676e5ccdac..ae6b5ca33a 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -27,7 +27,7 @@ PDFPAGES = testcurl.pdf runtests.pdf
 MANDISTPAGES = runtests.1.dist testcurl.1.dist
 
 EXTRA_DIST = appveyor.pm azure.pm badsymbols.pl check-deprecated.pl CMakeLists.txt \
- dictserver.py directories.pm disable-scan.pl error-codes.pl extern-scan.pl FILEFORMAT.md \
+ devtest.pl dictserver.py directories.pm disable-scan.pl error-codes.pl extern-scan.pl FILEFORMAT.md \
  processhelp.pm ftpserver.pl getpart.pm globalconfig.pm http-server.pl http2-server.pl \
  http3-server.pl manpage-scan.pl manpage-syntax.pl markdown-uppercase.pl mem-include-scan.pl \
  memanalyze.pl negtelnetserver.py nroff-scan.pl option-check.pl options-scan.pl \
diff --git a/tests/devtest.pl b/tests/devtest.pl
new file mode 100755
index 0000000000..1535423c27
--- /dev/null
+++ b/tests/devtest.pl
@@ -0,0 +1,193 @@
+#!/usr/bin/env perl
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) Daniel Fandrich, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+# SPDX-License-Identifier: curl
+#
+###########################################################################
+
+# This script is intended for developers to test some internals of the
+# runtests.pl harneess. Don't try to use this unless you know what you're
+# doing!
+
+# An example command-line that starts a test http server for test 11 and waits
+# for the user before stopping it:
+#   ./devtest.pl --verbose serverfortest https echo "Started https" protoport https preprocess 11 pause echo Stopping stopservers echo Done
+# curl can connect to the server while it's running like this:
+#   curl -vkL https://localhost:<protoport>/11
+
+use strict;
+use warnings;
+use 5.006;
+
+BEGIN {
+    # Define srcdir to the location of the tests source directory. This is
+    # usually set by the Makefile, but for out-of-tree builds with direct
+    # invocation of runtests.pl, it may not be set.
+    if(!defined $ENV{'srcdir'}) {
+        use File::Basename;
+        $ENV{'srcdir'} = dirname(__FILE__);
+    }
+    push(@INC, $ENV{'srcdir'});
+}
+
+use globalconfig;
+use servers;
+use runner qw(
+    readtestkeywords
+    singletest_preprocess
+);
+use getpart;
+
+
+#######################################################################
+# logmsg is our general message logging subroutine.
+# This function is currently required to be here by servers.pm
+# This is copied from runtests.pl
+#
+my $uname_release = `uname -r`;
+my $is_wsl = $uname_release =~ /Microsoft$/;
+sub logmsg {
+    for(@_) {
+        my $line = $_;
+        if ($is_wsl) {
+            # use \r\n for WSL shell
+            $line =~ s/\r?\n$/\r\n/g;
+        }
+        print "$line";
+    }
+}
+
+#######################################################################
+# Parse and store the protocols in curl's Protocols: line
+# This is copied from runtests.pl
+#
+sub parseprotocols {
+    my ($line)=@_;
+
+    @protocols = split(' ', lc($line));
+
+    # Generate a "proto-ipv6" version of each protocol to match the
+    # IPv6 <server> name and a "proto-unix" to match the variant which
+    # uses Unix domain sockets. This works even if support isn't
+    # compiled in because the <features> test will fail.
+    push @protocols, map(("$_-ipv6", "$_-unix"), @protocols);
+
+    # 'http-proxy' is used in test cases to do CONNECT through
+    push @protocols, 'http-proxy';
+
+    # 'none' is used in test cases to mean no server
+    push @protocols, 'none';
+}
+
+
+#######################################################################
+# Initialize @protocols from the curl binary under test
+#
+sub init_protocols {
+    for (`$CURL -V 2>/dev/null`) {
+        if(m/^Protocols: (.*)$/) {
+            parseprotocols($1);
+        }
+    }
+}
+
+
+#######################################################################
+# Initialize the test harness to run tests
+#
+sub init_tests {
+    init_protocols();
+    initserverconfig();
+}
+
+#######################################################################
+# Main test loop
+
+init_tests();
+
+#***************************************************************************
+# Parse command-line options and commands
+#
+while(@ARGV) {
+    if($ARGV[0] eq "-h") {
+        print "Usage: devtest.pl [--verbose] [command [arg]...]\n";
+        print "command is one of:\n";
+        print "  echo X\n";
+        print "  pause\n";
+        print "  preprocess\n";
+        print "  protocols *|X[,Y...]\n";
+        print "  protoport X\n";
+        print "  serverfortest X[,Y...]\n";
+        print "  stopservers\n";
+        print "  sleep N\n";
+        exit 0;
+    }
+    elsif($ARGV[0] eq "--verbose") {
+        $verbose = 1;
+    }
+    elsif($ARGV[0] eq "sleep") {
+        shift @ARGV;
+        sleep $ARGV[0];
+    }
+    elsif($ARGV[0] eq "echo") {
+        shift @ARGV;
+        print $ARGV[0] . "\n";
+    }
+    elsif($ARGV[0] eq "pause") {
+        print "Press Enter to continue: ";
+        readline STDIN;
+    }
+    elsif($ARGV[0] eq "protocols") {
+        shift @ARGV;
+        if($ARGV[0] eq "*") {
+            init_protocols();
+        }
+        else {
+            @protocols = split(",", $ARGV[0]);
+        }
+        print "Set " . scalar @protocols . " protocols\n";
+    }
+    elsif($ARGV[0] eq "preprocess") {
+        shift @ARGV;
+        loadtest("${TESTDIR}/test${ARGV[0]}");
+        readtestkeywords();
+        singletest_preprocess($ARGV[0]);
+    }
+    elsif($ARGV[0] eq "protoport") {
+        shift @ARGV;
+        my $port = protoport($ARGV[0]);
+        print "protoport: $port\n";
+    }
+    elsif($ARGV[0] eq "serverfortest") {
+        shift @ARGV;
+        my ($why, $e) = serverfortest(split(/,/, $ARGV[0]));
+        print "serverfortest: $e $why\n";
+    }
+    elsif($ARGV[0] eq "stopservers") {
+        my $err = stopservers();
+        print "stopservers: $err\n";
+    }
+    else {
+        print "Error: Unknown command: $ARGV[0]\n";
+        print "Continuing anyway\n";
+    }
+    shift @ARGV;
+}